5.12.08

CNN's taking charge



The Green Revolution- it cant succeed if it isn't known, it won't be known if we don't spread the word. I'm glad CNN is doing it's part in helping the cause instead of selling out to large corporations much like many other media organizations (hint Fox).

- Jassa Sidhu

STRAW BALE BUILDING

Straw is the dry stalks of harvested wheat, barley and other cereal plants. Tightly baled and used for exterior walls, straw is a strong, non-toxic building material with great durability. As with any straw bale construction, Tenax, a plastic mesh, keeps the straw in place and provides a base for the cement plaster that covers the interior and exterior.

A breathable, silicate-based paint covers interior and exterior walls, allowing moisture to pass from the house through the straw and ensuring the bales stay dry -- no vapour barrier is necessary in straw bale construction. It's hard to beat straw bales' insulating value, which proponents claim has an R value of 35 to 50, double to triple that of a conventional wall.

Any type of straw can be used, including wheat, oats, barley, rye and rice. Bales used for building are not custom-baled, but must be dry (less than 20% moisture) and tight. Two string bales are the Canadian straw bale construction standard, but in places where larger, three-string bales are the norm they too can be used and offer insulation values of R-55.

Straw bale buildings use the same foundation, flooring and roofing technologies familiar to builders of frame homes. Basements, slabs and pier foundations can all be easily adapted to straw bale construction. Similarly, prefabricated trusses can be used to provide the roof structure.

The straw bales in the walls are stacked in a manner similar to bricks or concrete blocks, in running bond. Window and door openings are created using wide, rough frame wooden bucks inserted into the walls during construction. The first course of bales is always started on a 2x4 curb, to lift the bales higher than the interior floor level, in case of flooding or spills.

There are two basic styles of straw bale construction. Post and beam style uses a structural framework to support roof loads, and the bales are either wrapped outside the framework or in filled between the framing members. While wooden post and beam systems are the most common, concrete and steel frames would also be suitable. Straw bales are a practical building material, abundantly available in most areas, and annually-renewable.


-chris c. --

Raising the (Green) Roof

Melbourne’s 6-star CH2 building

Newsflash: Green roofs aren't just for hobbits anymore. People are finally realizing the benefits of Green roofs, which are planted roofs—"usually made up of hardy, succulent sedums--can absorb storm water, helping to relieve our backed up storm pipes and drains, since loads of impervious surfaces—parking lots, driveways, etc". They are known to help reduce greenhouse gases and even act as insulators for buildings allowing them to be more energy efficient. In addition to these benefits, the lecture by Anna Toumai, stressed its benefits in a more social context. This was a refreshing intake on our generally 'eco-friendly' take on Green roofs. Where we can begin to see them as aesthetically pleasing social spaces in addition to their already beneficial nature.

- Jassa

GREEN ROOF WINNIPEG


Funded by the FCM grant, the City of Winnipeg explored the feasibility of developing a green roof strategy for flat-topped buildings in its downtown area. Such a strategy could help alleviate stormwater management problems in Winnipeg’s downtown. The City felt that a green roof strategy could be incorporated into the Combined Sewer Overflow (CSO) control model to reduce runoff effects and provide other environmental benefits.
The Assiniboine district was the focus of this study due to its high concentration of flattopped buildings. The area is also the most prone to overflows from the combined sewer system. Recent aerial photographs and visual inspections indicated that an area of 218,773 square metres (almost 20% of the total area of the district) could be used for green roof development.
Control-system models were created to simulate rainfall and runoff during a typical year. Various scenarios were examined to determine whether a green roof strategy could reduce not only the number of overflows in a year, but also their volume and the volume of wastewater going to the water pollution control center.
In this study plant species were also evaluated for their carbon-fixation and sequestering potential.
Data collected during the stormwater modeling process indicated that the number of overflows could be reduced by 16%, if 100% of the potential roof space in the district were used. The volume of the overflow could also be reduced by approximately 48%, which in turn would cut the volume of flow to the water pollution control centers. In terms of the carbon fixation it was found that if 100% of the potential green roof space were developed, 24.5 tonnes of carbon would be fixed (removed) annually.

--chris c.--

The Living Wall is needed downtown


Along with green roofs there are living walls. A living wall is either part of a building or free standing which is at least partially covered in vegetation and sometimes soils and other organic growing material. They are also referred to as green walls or biowalls. I believe that each building in the downtown area should have at least one living wall because at least then there is some green space in the district. By having green walls in office buildings, people may be better able to cope with what is known as sick building syndrome. Living Walls would also be a very easy way of reusing the greywater from the building. It would require no remodeling of the building in certain ways such as sending the greywater straight to the “free standing wall.” Beyond all of the ways they help create a healthy living environment, living walls also are very aesthetically pleasing to the eye.

The Living Wall

~Trevor